In the prior art, the patent document with publication No. CN101885110A discloses a rotational position detecting apparatus that uses two rotators having different periods of rotation. Each rotator is provided with one or more claws and corresponding claw sensors for detecting the angle and number of rotation. As a result, the manufacturing cost of the detecting apparatus is increased due to the provision of the plurality of rotators, and the adjustment and maintenance cost is increased due to the increased number of components.